Erecting-type wheelchairs, particularly of the motorized type, are expensive. Wheelchairs can be matched only to a limited extent to the size of the patient. Erecting-type wheelchairs for children were practically unavailable. A limited degree of adjustability is provided by placing length-adjustable elements on footrests. The length of the seat, and the positioning of the backrest with respect to the seat, cannot be adjusted. To make such wheelchairs suitable for persons of different sizes, and particularly for growing children, it was customary to use cushions or other makeshift arrangements in order to provide the required space between the back of the erecting wheelchair and the seating surface if the chair was to be used by smaller persons.
It has previously been proposed--see Published European Application No. 0 018 101--to construct the side frame of a collapsible wheelchair in such a manner that telescopic elements are used which permit changing the distance between the wheels of the wheelchair. Attachment elements are provided at various positions of the side frame to permit, selectively, installation of a larger or a smaller main wheel. The structure described in this application permits varying the width of a seat; since, however, the arrangement refers to an ordinary type of wheelchair--not an erecting-type wheelchair--no solution to match an erecting-type wheelchair to different sizes of patients is given. Erecting-type wheelchairs require a separate seating and erecting frame.
A collapsible wheelchair is further shown in U.S. Pat. No. 4,082,348, which permits adjusting the height of the seating surface by carrying the seat by telescopically fitting tubes. The positioning, that is, the telescopic fit of the tubes, is determined by suitable holding elements. The length of the seat cannot, however, be matched to a particular person, so that a standard size of this type wheelchair is not suitable for use with children or for persons of unusual height.